Expression of preprotachykinin-A mRNA isoforms and substance P production in T lymphocytes of human healthy subjects

The influence of sex and age on the expression pattern of preprotachykinin-A (PPT-A) mRNA isoforms encoding substance P and other tackykinins such as neurokinin A (NKA), neuropeptide K (NPK) and neuropeptide γ (NPγ) in human immunocompetent cells and the role of this pattern on SP production are unknown. To investigate these questions, we assessed PPT-A isoform expression and SP production in CD3+ lymphocytes of normal healthy subjects. There were no significant differences in PPT-A isoforms in relation to sex or age. The most frequently expressed isoforms were β and γ: after lymphocyte stimulation with phytohemagglutinin (PHA), there was a significant increase in their frequency (p < 0.0001). Significantly higher SP levels were found in subjects expressing β and γ PPT-A than in those with β PPT-A only (p = 0.001). These findings provide evidence of a heterogeneous expression of PPT-A isoforms in CD3+ lymphocytes of normal healthy subjects.